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C Wolfson

Publications and source records attributed to C Wolfson.

At least 19 recordsLinked to original sources
PubMed1998

Imaging axonal damage of normal-appearing white matter in multiple sclerosis.

The current study was designed to determine the relative distribution of decreases of N-acetylasparate (NAA), a marker of axonal damage, between lesions and normal-appearing white matter of patients with established multiple sclerosis and to test for associations between changes in the ratio of NAA to creatine/phosphocreatine (NAA:Cr) in those compartments and changes in disability. Data were collected from a 30-month longitudinal study of 28 patients with either a relapsing course with partial remissons and no progression between attacks (relapsing/remitting) (11 patients) or a course of progressively increasing disability, following a period of relapsing/remitting disease (secondary progressive) (17 patients). Proton magnetic resonance spectroscopic imaging (MRSI) and conventional MRI examinations were performed at 6-8-month intervals with concurrent clinical assessments of disability. General linear models were used to test associations between MRSI, MRI, lesion volume and clinical data. Analysis confirmed that the NAA:Cr ratio is lower in lesions than in the normal-appearing white matter (-15.3% in relapsing/remitting multiple sclerosis and -8.8% in secondary progressive multiple sclerosis). The lower NAA:Cr ratio per unit lesion volume previously observed for secondary progressive relative to relapsing/remitting patients was found to result from a lower ratio (8.2%, P < 0.01) in the normal-appearing white matter rather than from any differences within lesions. The importance of changes in the normal-appearing white matter was emphasized further with the observation that the NAA:Cr ratio in the normal-appearing white matter accounted for most of the observed 15.6% (P < 0.001) decrease in the NAA:Cr ratio in the brains of relapsing/remitting patients over the period of study. The decrease in the NAA:Cr ratio in normal-appearing white matter correlated strongly (P < 0.001) with changes in disability in the relapsing/remitting subgroup. These results add to data suggesting that axonal damage or loss may be responsible for functional impairments in multiple sclerosis. The accumulation of secondary axonal damage in the normal-appearing white matter may be of particular significance for understanding chronic disability in this disease.

Aspartic Acid↗
PubMed1997

Randomised trial of home-based psychosocial nursing intervention for patients recovering from myocardial infarction.

BACKGROUND: Increases in life stress have been linked to poor prognosis, after myocardial infarction (MI). Previous research suggested that a programme of monthly screening for psychological distress, combined with supportive and educational home nursing interventions for distressed patients, may improve post-MI survival among men. Our study assessed this approach for both men and women. We aimed to find out whether the programme would reduce 1-year cardiac mortality for women and men. METHODS: We carried out a randomised, controlled trial of 1376 post-MI patients (903 men, 473 women) assigned to the intervention programme (n = 692) or usual care (n = 684) for 1 year. All patients completed a baseline interview that included assessment of depression and anxiety. Survivors were also interviewed at 1 year. FINDINGS: The programme had no overall survival impact. Preplanned analyses showed higher cardiac (9.4 vs 5.0%, p = 0.064) and all-cause mortality (10.3 vs 5.4%, p = 0.051) among women in the intervention group. There was no evidence of either benefit or harm among men (cardiac mortality 2.4 vs 2.5%, p = 0.94; all-cause mortality 3.1 vs 3.1%, p = 0.93). The programme's impact on depression and anxiety among survivors was small. INTERPRETATION: Our results do not warrant the routine implementation of programmes that involve psychological-distress screening and home nursing intervention for patients recovering from MI. The poorer overall outcome for women, and the possible harmful impact of the intervention on women, underline the need for further research and the inclusion of adequate numbers of women in future post-MI trials.

Aged↗
PubMed1997

HM-PAO (CERETEC) SPECT brain scanning in the diagnosis of Alzheimer's disease.

OBJECTIVE: To evaluate the accuracy of Single Photon Emission Computed Tomography (SPECT) scanning in the diagnosis of Alzheimer's Disease (AD) and its capacity to improve the diagnostic accuracy of conventional clinical evaluation. DESIGN: Comparison of SPECT scanning of AD and normal subjects with the criterion standard of clinical diagnosis confirmed by 1-year repeated evaluation. SETTING: A memory clinic in a tertiary care university hospital. PATIENTS: One hundred twenty patients were evaluated upon entering the Jewish General Hospital (McGill University) Memory Clinic. Fifty-eight patients were diagnosed as having AD and 17 as having vascular dementia. Twenty unmatched controls (recruited mainly through newspaper advertisements) were normal, and 25 had cognitive impairment without dementia (not included in the statistical analysis). MAIN OUTCOME MEASURES: Comparison of visual inspection of SPECT, based on the system of classification developed by Holman et al., using B pattern alone as positive or B (bilateral posterior temporal and/or parietal cortex deficits) or C (bilateral posterior temporal and/or parietal deficits with additional defects) pattern and B or C or D (unilateral posterior temporal and/or parietal defects with or without additional defects) as positive compared with clinical diagnosis after repeated evaluations. Sensitivity and specificity, as well as positive predictive value (PPV) and negative predictive value (NPV) based on the prevalence of AD in a memory clinic setting of 30% or 50%, were calculated. RESULTS: With B pattern as positive, the sensitivity of SPECT was 21% whereas the specificity was 80%. With B or C as positive, the sensitivity was 29% and the specificity was 75%. With B or C or D as positive, the sensitivity was 55% and the specificity was 65%. With a 30% prevalence, the PPV with B pattern as positive was 31% whereas the NPV was 30%. The PPV with B or C as positive was 33% while the NPV was 29%, and the PPV with B or C or D as positive was 40% whereas the NPV was 23%. With a 50% prevalence, the PPV with B pattern as positive was 51% and the NPV 49.6%; the PPV with B or C as positive was 54% and the NPV 48.6%; the PPV with B or C or D as positive was 61% while NPV was 41%. CONCLUSION: The sensitivity and specificity were too low for SPECT to be useful as a diagnostic test for AD. The poor positive and negative predictive values in our tertiary care clinic mean that SPECT is not useful in "ruling-in" or "ruling-out" AD in that setting. In fact, clinical evaluation is more accurate.

Aged↗
PubMed1996

Statistics for investigation of multimodal MR imaging data and an application to multiple sclerosis patients.

Magnetic resonance spectroscopy can image axonal damage specifically based on changes in N-acetyl aspartate (NAA), a neuronal marker. We have developed statistical methods for multimodal analysis of MR spectroscopic images. These methods, which are extensions of mixed-effect models, have allowed us to quantify differences in images from different subgroups of patients with multiple sclerosis (MS) and to determine the dependence of chemical pathology on clinical disability, duration of disease and lesions on T2-weighted MRI. Statistical power was improved by using all reliable resonance intensities in the spectroscopic images while taking into consideration the intra-subject correlations. We studied 17 normal subjects, 14 patients with relapsing remitting (RR) MS and 21 patients with chronic progressive (CP) MS. The ratio of resonance intensities of N-acetylaspartate over creatine (Cr) was found to be significantly lower than normal in normal appearing white matter (NAWM) of both RR and CP patients (19.6% in RR, 28.8% in CP), NAA/Cr was decreased even more in MS plaques than in NAWM (44.2% in RR, 17.7% in CP), NAA/Cr was correlated with clinical disability (p < 0.02) and disease duration (p < 0.1). Our results suggest that, in this setting, MRS reflects accumulated neuronal loss or damage and can be used as a measure of disease severity. The methods developed provide opportunities to evaluate the relationship between inflammation, demyelination, axonal loss and clinical disability in future studies.

Aspartic Acid↗
PubMed1996

Prevalence of Bartonella henselae bacteremia, the causative agent of cat scratch disease, in an Australian cat population.

In order to determine the prevalence of Bartonella henselae becteremia in an Australian cat population we examined blood cultures on a group of Sydney cats. Cats referred to the Concord Animal Hospital for euthanasia were selected randomly for blood culture and serum sampling. Blood samples were lysed and centrifuged and then cultured for up to five weeks. Suspicious colonies were identified biochemically as probable B. henselae. Selected isolates were confirmed as B. henselae using the polymerase chain reaction. Of the cats accrued throughout Sydney, 27/77 (35%) were culture positive for B. henselae, of these 24/59 (40%) were feral cats and 3/18 (16%) were domestic. Most cats in the study were younger than one year (mean 9.9 months). Our study demonstrates that bacteremia with B. henselae is common in the metropolitan cat population and suggests that it is particularly prevalent among feral animals. By contrast Cat Scratch Disease (CSD) is a relatively uncommon clinical diagnosis in the Australian population. Explanations for this discrepancy may include poor transmission, low bacterial virulence and underdiagnosis. It is possible that feral animals are a greater potential risk source for this infection than domestic cats.

Animals↗
PubMed1996

Assessment of lesion pathology in multiple sclerosis using quantitative MRI morphometry and magnetic resonance spectroscopy.

Quantitative measurement of MRI-defined brain lesions can provide an index of the extent and activity of disease in multiple sclerosis patients. However, the relationships between these indices and clinical features are not well-understood. Heterogeneity of the pathological changes underlying MRI lesions may be an important factor determining the correlation between MRI lesion volumes and clinical measures. Recent studies have suggested that with magnetic resonance spectroscopy (MRS), it may be possible to define chemical changes that better reflect the pathological changes in multiple sclerosis. Here we report results of combined quantitative brain T2-weighted MRI lesion volume and proton MRS examinations that demonstrate heterogeneity of the chemical pathology underlying brain lesions in patients selected on the basis of similar clinical disability but differing with respect to the presence or absence of clinical relapses. We examined 29 patients with disease characterized by either clear relapses with at least partial remissions (RR) or secondary, chronic progression after an earlier history of a more relapsing and remitting course (SP). Total hemispheric lesion volume was greater (P < 0.04) in the RR (32.5 +/- 20.9 cm3) than in the SP (16.2 +/- 9.0 cm3) patients, despite the longer duration of disease in the latter group. Central brain N-acetyl aspartate: creatine (NAA:Cr) ratios were reduced relative to normal controls (4.0 +/- 0.3, n = 19) by similar amounts in the two patients groups (RR, 3.1 +/- 0.5; SP, 3.2 +/- 0.4; P < 0.0001). The ratio lesion volume:(NAA:Cr) was greater for the RR group (11.7 +/- 9.3 cm3) than for the SP group (5.4 +/- 3.3 cm3, P < 0.05), implying a greater average degree of axonal loss per unit lesion volume defined by MRI for subjects in the SP group or, alternatively, a greater proportion of lesions without axonal damage or loss in the RR group. Our results emphasize a limitation of using T2-weighted MRI lesion volume alone and suggest that combined analysis of MR-based chemical and imaging data might allow improved non-invasive assessment of lesion pathology in order to better understand its relationship to clinical features of multiple sclerosis.

Adult↗
PubMed1996

Organic solvents and multiple sclerosis: a synthesis of the current evidence.

To evaluate the possible relation between exposure to organic solvents and the development of multiple sclerosis, we carried out a best-evidence synthesis of the available information. We found 13 studies with varying methodology that included information on solvent exposure. In 10 of the studies, there were indications of an increased risk of multiple sclerosis in relation to solvent exposure. We made three selections of studies for both pooled analyses and meta-analyses. The relative risk point estimates that we obtained varied from 1.7 to 2.6. Our evaluation is consistent with the hypothesis that organic solvents may be a cause of multiple sclerosis.

Case-Control Studies↗
PubMed1996

The Etest for antimicrobial susceptibility testing of Bartonella henselae.

The in-vitro susceptibility of 10 isolates of Bartonella henselae was assessed using the Etest. The organisms, one reference human strain and nine feline isolates, were grown on chocolate agar and the Etests read at days 5, 8 and 11. Six antibiotics, erythromycin, azithromycin, doxycycline, ciprofloxacin, rifampicin and vancomycin were evaluated. The results correlated well with published results using agar dilution. The results confirmed the high in-vitro susceptibility of B. henselae to erythromycin, azithromycin, doxycycline and rifampicin and to a lesser extent ciprofloxacin. The majority of isolates were resistant to vancomycin. Although in-vitro results of B. henselae susceptibility testing may not necessarily correlate with clinical response, the Etest may be a simpler way for laboratories to monitor for the development of resistance particularly in the setting of relapsing infection.

Animals↗
PubMed1995

Validation of a French version of an informant-based questionnaire as a screening test for Alzheimer's disease.

BACKGROUND: Development of informant-based screening tests for dementia is an emerging field. The reliability and validity of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), an instrument that screens for dementia in general, have been established. We conducted a study to validate a French version of the IQCODE as a screening test for Alzheimer's dementia in the elderly living in the community. METHOD: In the Canadian Study of Health and Aging, subjects were screened in their own homes using the modified Mini-Mental State Exam (3-MS). Those who screened positive, along with a sample of subjects who screened negative, were referred for a complete clinical examination. In Quebec, an informant was asked to complete the French version, IQCODE(F), at that time. Based on the final clinical diagnoses, performances of the IQCODE(F) and Mini-Mental State Examination (MMSE, converted from 3-MS) in screening for Alzheimer's disease were evaluated. RESULTS: Of the 237 subjects, the mean IQCODE (F) score was 3.4 (s.d. = 0.6), on a 5-point scale (1 = improvement in condition over the past 10 years, 5 = marked deterioration, 3 = no change). The mean MMSE score was 23.1 (s.d. = 4.5). The scores on the two scales were correlated (r = -0.44, P < 0.001). The IQCODE(F) scores were unrelated to education (r = -0.07, P > 0.3) in contrast to the MMSE scores (r = 0.28, P < 0.001). With respect to a diagnosis of probable Alzheimer's disease, the IQCODE(F) (cut-off point 3.6) had a sensitivity of 75% and a specificity of 95.6%. The sensitivity and specificity of the MMSE (cut-off point 23) were 70% and 82.3% respectively. CONCLUSION: The findings of the IQCODE(F) are consistent with those of the English version in correlation with the MMSE and apparent freedom from educational bias. The IQCODE is superior to the MMSE as a screening test for probable Alzheimer's disease in the elderly living in the community. It may be a useful addition to the screening tests already available, especially for the less well educated.

Aged↗
PubMed1994

Use of proton magnetic resonance spectroscopy for monitoring disease progression in multiple sclerosis.

Decreases in brain N-acetylaspartate are associated with neuronal loss or dysfunction. We report a longitudinal study in which changes in the N-acetylaspartate to creatine resonance intensity ratio measured by brain proton magnetic resonance spectroscopy were used to follow the progression of brain pathology in 7 patients with multiple sclerosis over an 18-month period. Four of the patients had a history of recurrent relapses and 3 had a secondary progressive course. All had clinical and magnetic resonance imaging evidence of persistent neurological abnormalities. At 6-month intervals proton magnetic resonance spectra were obtained and the N-acetylaspartate-creatine ratio was determined for each patient. The volumes of hyperintense signal from lesions on conventional magnetic resonance images and the Kurtzke Expanded Disability Status Scale scores were determined concurrently. At the onset of the study, the N-acetylaspartate-creatine ratio was significantly (p < 0.05) lower in the central brain volumes from the patients than in 13 normal control subjects. At 12 and 18 months of follow-up, the ratio had decreased further in all patients (p < 0.05), consistent with progressive accumulation of neuronal damage. In contrast to magnetic resonance spectra data, changes in lesion volume on magnetic resonance images or disability status did not reach significance over this period. Subgroup analysis showed that changes (increases or decreases) in the N-acetylaspartate-creatine ratio between consecutive 6-month examinations correlated significantly (r = -0.74, p < 0.005) with changes in lesion volume on magnetic resonance images in patients with a history of relapses.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspartic Acid↗
PubMed1994

Hemostatic markers in acute transient ischemic attacks.

BACKGROUND AND PURPOSE: Hemostatic abnormalities have been shown previously in stroke patients. The purpose of this study was to assess the activity of selected parameters of the coagulation system in acute reversible cerebral ischemia. METHODS: We measured fibrinopeptide A, thrombin-antithrombin III, and D-dimer in 36 patients in both the acute (< 7 days) and postacute stage (1 and 3 months) after a transient ischemic attack (TIA). The results were compared with those of 20 asymptomatic patients with a history of remote TIA and 65 age- and sex-matched controls. RESULTS: Mean fibrinopeptide A and thrombin-antithrombin III values were elevated in the acute stage after a TIA (P < .02) compared with levels at 1 month. In contrast, D-dimer was significantly increased at all three times points after the event when compared with remote TIA (P < .05) or control subjects (P < .001). No association could be found between marker levels and clinical outcome or the degree of cervical atherosclerosis as assessed by duplex ultrasonography. CONCLUSIONS: These findings suggest that after acute reversible cerebral ischemia, there is early transient activation of thrombogenesis and ongoing fibrinolysis.

Aged↗
PubMed1993

Adult children's perceptions of their responsibility to provide care for dependent elderly parents.

We examined how adult children in Canada whose parents were hospitalized in an acute care setting perceived responsibility for their parents' care. Using a visual analogue scale, adult children rated the amount of financial, emotional, and physical support families "should" and "could" give to elderly persons described in four vignettes. All scores were high, with "should" consistently higher than "could" for every vignette and for each of the three types of support. For daughters, the more aggressive the parent, the lower the "should" score for financial support. The same relationship was observed for incontinence and these findings were consistent over all four vignettes.

Adult↗
PubMed1993

The latent period of multiple sclerosis: a critical review.

It is a widely held belief that multiple sclerosis is a disease with a long latent period that is preceded by heightened susceptibility before adolescence. There has, however, been little research focused on either the estimation of the latent period or determination of the susceptibility period. In this article, we present a critical assessment of the relevant literature on migrant studies, cluster studies, the Faroe Islands "epidemic," sibling study, and novel statistical approaches as they pertain to the pre-onset natural history of multiple sclerosis. We also discuss the roles of the latent and susceptibility periods in the design, analysis, and interpretation of epidemiologic studies.

Adolescent↗
PubMed1993

Multiple sclerosis: a comparison of the latent periods of different populations.

While some research in multiple sclerosis has concentrated on the latent period of this disease in single population groups, none has attempted to carry out significance tests to compare the distributions of the latent periods of two distinct groups. Two comparisons are made here, between the populations attending the Multiple Sclerosis Clinic of the Montreal Neurological Institute and Hôpital Neurologique et Neuro-Chirurgical Pierre-Wertheimer, Lyon. We also compared the latent period separately in males and females. There were no significant differences. The significance tests and power studies were based on a nonparametric model that allows for uncertainty in the ages of disease initiation as well as in the ages of onset.

Adolescent↗